We read this article with interest. We were dismayed to learn that the authors considered CVCI a rare scenario when they stated that in a survey 57% of Canadian anaesthetists had personally encountered such a situation. This is not, therefore, rare. What is confusing is, perhaps, the unknown frequency with which it is encountered (not stated in the original survey). The probability of CICV is indeed rare at 0.1-0.2 % [1, 2]. We wonder why so many Canadian anaesthetists are quoted as encountering CICV. The authors have accurately quoted the original paper by Wong et al but have not explained the apparent wider experience of the Canadians of CICV.

D. Kruchek

J. Mathew

M. Kayani

Ashford & St Peter's Hospital NHS Trust

Chertsey, UK

References

1. Combes X, Le Roux B, Suen P, et al. Unanticipated difficult airway in   anesthetized patients: prospective validation of a management algorithm. Anesthesiology 2004; 100: 1146–50.

2. El-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative airway   assessment: predictive value of a multivariate risk index. Anesthesia and Analgesia 1996; 1197–204.